This movie shows a
history in which mountains are eroded to a low plain that is then covered
by a succession of younger layers. The buried erosion surface, between the
older tilted layers and the younger horizontal ones, is an unconformity.
An unconformity represents a long time interval between the deposition of layers.
Within this break in time, layers that were previously deposited can be tilted, folded, faulted, and/or intruded and then eroded. After the
tilting, folding, etc., new layers are deposited on top
of this surface. An unconformity can also be tilted after it is
formed. When in this movie does the unconformity form?